AMDKFD Looking To Be Merged Into AMDGPU Linux DRM Kernel Driver

While "AMDGPU" is often what is talked about when it comes to the Radeon graphics driver code within the Linux kernel with it being the Direct Rendering Manager (DRM) driver for AMD GCN graphics cards and newer, there is also the AMDKFD kernel driver that plays a vital role for compute support.

AMDKFD is the AMD Kernel Fusion Driver (dating back to the days of AMD "Fusion") that is basically the AMD HSA compute driver within the kernel. AMDKFD is needed to work with the user-space ROCm/OpenCL compute components and in recent kernel releases is working out well just not for AMD APUs but also the discrete graphics cards. After relying upon out-of-tree kernel code for a while to get good compute support going, with Linux 4.17~4.18, things are looking bright.

Now AMD is discussing the merger of the AMDKFD driver code into the AMDGPU DRM driver itself. AMDKFD already lives within the DRM subsystem while now with the mainline/upstream state of this compute code being in good shape, they are looking at merging it into this single driver. Another reason why it wasn't merged previously is that for a while, AMDKFD also supported the Radeon DRM driver too rather than just AMDGPU, but with recent kernels only AMDGPU DRM is supported anyways.

AMDKFD code would roughly be structured as another component to AMDGPU, like DAL/DC is for the modern display code support within AMDGPU. This merging would also allow some simplification of the code to be improved upon in the process, removing some duplicated code between the two drivers, etc.

Initial plans for the AMDKFD-AMDGPU merger can be found via the mailing list. It's likely this will take a while to happen, so is probably not something to look forward to seeing with Linux 4.19 but perhaps we will see it in Linux 5.0.